1. Field of the Invention
The present invention relates to a manufacturing method of a flying magnetic head slider provided with a thin-film magnetic head element.
2. Description of the Related Art
In a magnetic disk drive device, thin-film magnetic head elements for writing magnetic information into and/or reading magnetic information from magnetic disks are in general formed on magnetic head sliders flying in operation above the rotating magnetic disks. The sliders are supported at top end sections of suspensions, respectively.
Recently, a flying height of the magnetic head slider rapidly lowers to satisfy the requirement for ever increasing data storage capacities and densities in today's magnetic disk drive apparatus. Because of such lowered flying height, a possible protrusion of a protection layer of the slider at a corner portion between an air bearing surface (ABS) and a trailing surface, which corner is the lowest portion of the slider during the flying operations has not become negligible. Particularly, in the magnetic head slider with an inductive write head element, a protection layer may thermally expand and protrude due to the write current causing the protruded portion to come into contact with the magnetic disk surface during operations.
Known is a method of forming a step or recess at a corner edge between the ABS and the trailing surface of the magnetic head slider, by partially removing the protection layer during a patterning process of the ABS, to reduce the protrusion of the protection layer as small amount as possible.
In another known method disclosed for example in U.S. Pat. No. 6,428,715 B1, protrusion of a protection or overcoat layer made of a typical material of alumina (Al2O3) is reduced by immersing the overcoat layer in an alkaline solution and thus by etching the whole ABS of the overcoat layer to form a step.
However, according to the former known method, due to the limited resolution of a resist and the limited precision in an exposure equipment used for patterning the ABS, it is impossible to bring a starting point of the step close to a magnetic pole of the inductive write head element. Therefore, the protrusion amount cannot be reduced so much. If the step is formed over a part of the magnetic pole, a coating film such as a diamond like carbon (DLC) film is removed causing corrosion of the pole to occur.
According to the latter known method, it is ensured to etch the alumina and to form a step. However, if the magnetic pole contains a metal material easily etched by an alkaline, the pole itself is etched to deteriorate the characteristics of the write head element.